Matrix Orbital VK204-25 Legacy - Manual (Page 6)

the baud rate to 19,200. If characters are typed on the keyboard, they should now appear on the display
screen. Text will wrap around to the next line when the end of a line has been reached.
A few common ASCII control characters work as follows;
Table 1: Common ASCII Control Characters
Character Hex value Function
CR 0x0D Moves cursor to beginning of the
current line.
LF 0x0A Moves cursor to beginning of the
next ( or previous ) line.
FF 0x0C Clears the display and puts the cur-
sor at the top left.
BS 0x08 Moves the cursor one position to the
left and clears that position.
NOTE These command characters are not guaranteed to work on other Matrix Orbital
display modules.
To exercise some of the other features of the display a program (in any convenient language such as Basic
or C) will need to be written in order to issue the required command strings. Most terminal programs are
unable to issue the 0xFE character needed as a command prefix.
1.6 Trying out a Keypad
Since a number of different keypad types can be connected to the display, the results may be a little
unpredictable. At this point all we need to do is make sure that the keypad and interface work, and possibly
generate an ASCII map for any programming needs. The keypad interface on the display converts a row /
column connection to an ASCII character. By default, a keypress is transmitted as serial data immediately.
Keypad buffering can be selected using the appropriate commands.
1.6.1 Here’s what to Do
1. The PC should be running a terminal program, such as Hyperterm.
2. With the display connected to the PC, plug in the keypad. If the connector has fewer pins than the one
on the display, center it as well as possible.
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